High-voltage Impulse Research Articles

Spatio-temporal evolution of ion current extracted from pulsed dielectric barrier discharge

In the present study, the influence of various factors on the shape of the ion cloud extracted from the specific discharge setup was investigated. The overall installment presented a surface dielectric barrier discharge plasma in the air fed by impulse high voltage. The effect of the amplitude, polarity, and duration for single and repetitive voltage pulses were examined. The patterns of ion current distribution depending on the gas gap length and the average field strength were obtained, and the effect of pulse duration and frequency on the amount of the extracted charge were examined. It was shown that the extracted charge was non-uniformly distributed in the gap volume during single and periodic voltage pulses. The effect of volume charge accumulation in the gap at high pulse repetition rate was shown. Computer simulations demonstrated that the main role in the ion cloud shape distortion was caused by the surface charge deposited on the dielectric barrier.

Usage of high voltage impulse generator to research the process of electropulse destruction of locust larvae in the soil

In accordance with announced technology, a laboratory research complex is needed for researching the influence of electropulse effects on locust larvae (capsules) and identification of the processing modes and construction design required to cause their irreversible (fatal) damage. In this regard, a schematic diagram of a laboratory research complex for electropulse processing has been developed and its structure has been determined. A separate question concerned a source of high voltage and a shaper of high-voltage impulses. A special design of a high-voltage impulse generator has been developed. This design can produce impact impulses of various durations - the impulse duration depends on the capacitive storage; with maximum amplitude of 16 kV and current per impulse of up to 400 A. The generator uses a capacitive storage discharge through a thyratron controlled by a microcontroller to the load. The proposed high-voltage impulse generator is necessary for researching the effect of electropulse high-voltage technology on the irreversible damage of locust larvae located in the soil layer, and for the experimental identification of the operating modes of the electrical part of the designed electrotechnological system, which allows for destruction of locust capsules directly in the field. The designed high-voltage generator was tested in operational mode when working with a load, which was the soil volume placed between the electrodes in the working chamber. The shape of the operational impulse and its parameters comply with predefined characteristics for electropulse cultivation of soil massif with locust larvae (capsules). After the tests, minor structural adjustments were made, and the generator itself was prepared for experimental studies in the laboratory.

RANCANG BANGUN ALAT PASTEURISASI NON THERMAL DENGAN PULSED ELECTRIC FIELD (PEF)

ABSTRACTPackaged beverages have become a product that is very much on the market both internationally and nationally. In the process of making packaged beverages, in order to last longer the microbes in the drink must first be inactivated in order for the drink to last longer, the microbial inactivation process in the drink is called pasteurization. Convernsional pasteurization is done by heating the drink to be in production. But the high temperature of the drink can change the taste, color, and even nutrition of the drink. This is underpinning the non-thermal pasteurization process by using high voltage impulses (Pulsed Electric Field,PEF). PEF is a technology that utilizes high voltage DC to produce a field between two electrodes. Pateurization occurs when between electrodes there is milk that is flowed with high voltage DC. High voltage generation is performed using flyback transformers with voltage output up to 30 kV. In the pasteurization process given 6 voltage variations namely 5, 10, 12,5, 15, 20, and 30 kV. Pasteurization results are then tested in fmipa microbiology laboratory to find out the success of the tools that have been made. In each voltage variation it is obtained that all treatments have reached pasteurized milk quality standards based on SNI where at 5kV voltage variation can inactivat microbes up to 83.33%, voltage variation of 10kV can inactivat microbes up to 94.5%, At a voltage variation of 12.5 kV can inactivae microbes up to 83.6%, 15kV voltage variation can inactivae microbes up to 88.8%, while voltage variation of 20 kV can inactivae microbes up to 84.2% and at voltage variation 30 kV can inactivae microbes up to 84.8%.Key Words: PEF, Flyback Transformer, ZVS Driver, Pasteurization.

Analysis of light emission and Schlieren from short gap high voltage streamers representing lightning impulses

Light emissions and Schlieren structures were simultaneously observed from streamers produced by tens of kilovolts 1.2/50 μs impulses, representing the high voltage component of lightning, applied across a 4 cm air gap between a variety of electrode geometries and a ground plane in an unconfined environment. The results demonstrated that the light emissions and Schlieren structures coincide along the same streamer filaments but on different timescales; the light existing only during the microsecond timeframe impulse whereas the Schlieren continued to develop into the millisecond timeframe, moving towards the centre of the air gap whilst diffusing into the surrounding air within 100 ms. If an electrical breakdown did occur, the Schlieren structures outside the arc remained visible. Streamer formation theory for high voltage impulses is subsequently refined to include the observed Schlieren mechanism.

Long‐Term Stability of Reference Measuring System for Impulse High Voltage

Long‐term stabilities of shielded resistive voltage dividers for lightning and switching impulse, employed as the reference dividers of Japan High‐voltage Impulse testing Laboratory Liaison (JHILL) are investigated. The DC scale factors and the step‐response parameters have been annually measured for 20 years. Annual variations of impulse parameters, namely the peak value, the front time, and the time to half value of the calculated waveform from the step‐response waveforms by the convolution algorithm are investigated. Furthermore, long‐term stabilities of reference low‐voltage impulse calibrators are investigated. The parameters of circuit elements of the calibrators have been annually measured for 18 years. The impulse parameters of the output waveforms of the calibrators are calculated, and the annual variations of them are investigated. After the detailed evaluation, it can be expected that the measurement system employing the voltage dividers and the calibrators, including the analytical method of the data, has the similar performance to those of NMIs of developed countries. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Change Character of Electric Conductive Properties of Weeds Plants Tissue at Electric Impulse Damage

Currently, in order to obtain pre-planned results and increase the efficiency of using existing technologies, electrotechnological operations are applied in the processes of agricultural production, food and processing industries, including those that implement the effects of high voltage impulses. One of such promising technologies in agriculture can be considered to be electric impulse weeding that is the fight against unwanted and weed vegetation. Such operation, which is carried out with high rates of technological efficiency, is environmentally friendly and refers to high-tech processes. For practical applications and technical implementations, it is necessary to study various properties and parameters of effected objects – weeds. The partial dependence of the electrical resistance of the plant tissue or the dispersion of resistance over the frequency of the measuring current was decided to be used as the studied characteristic. This approach allows to consider weeds not only as a load with which the electrical energy supply system is in contact but also to thoroughly study how this resistance changes during processing. The conducted experimental studies made it possible to clarify the nature of the change in resistance under the damage process to plant tissue, as well as to estimate the quantitative indicators of both the energy absorbed by the plant tissue and the ranges of variations of its resistance. The change character in the plant tissue resistance at the process of the electrical impulse damage remains unchanged, only the resistance value at low frequencies decreases. The total damage corresponds to the period of processing when the resistance of the plant tissue is practically equal at low and high frequencies. This behavior of the mentioned parameter is typical for internal and surface tissues of weeds, as well as for their root systems and leaf-stem parts. Theoretical verification of the change character in the plant tissue resistance of destroyed weeds confirmed the description of the proposed mechanism of change in resistance in the process of irreversible electrical impulse damage.

Development of technologies for production of fuel with minor actinides

The main results and plans for the future in the framework of R&D on the involvement of americium, neptunium (MA) in mixed nitride fuel of fast reactors are presented. Depending on the method and amount of MA introduced into the mixed nitride, R&D is carried out in three directions: homogeneous introduction of minor actinides; intra-fuel pin heterogeneity and intra-fuel assembly (FA) heterogeneity of minor actinides. At the first stage, the technology of homogeneous transmutation is being tested using dismountable FA (OU) in the BOR-60 reactor. Each OU includes 7 fuel pins. An intermediate unloading of fuel pins is planned with the corresponding additional loading of new ones and irradiation prolongation. The irradiation parameters of subsequent experimental fuel pins with MA will be specified after determining the characteristics of fuel pellets of mixed nitride with MA. In order to study the effect of MA additives on the cladding corrosion from the first batches of pellets, at the end of 2018, three experimental fuel pins with Np and Am with pellet density of ~10 g/cm3 in OU-16 were manufactured and loaded in BOR-60. Upon reaching the maximum fuel burn-up of 1.36 at% and a dose of 10.7 displacements per atom (dpa) OU-16 was unloaded for intermediate examination of fuel pins with MA. To minimize the loss of Am at the stage of fuel pellets sintering, the method of high-voltage electric impulse consolidation for pellets with Am is considered.

The Effect of Match between High Power Impulse and Bias Voltage: TiN Coating Deposited by High Power Impulse Magnetron Sputtering

Practical experience in the use of high power impulse magnetron sputtering (HiPIMS) technology has revealed that output bias current depends on the total energy output of the cathodes, which means that bias voltage settings do not necessarily match the actual output. In this study, we investigated the effects of bias current and voltage on the characteristics of titanium nitride thin films produced using high impulse magnetron sputtering. The bias current and voltage values were adjusted by varying the supplied cathode power and substrate bias under DC and pulsed-DC output models. Our results revealed that pulse delay (PD) and feed forward (FF) settings can be used to control bias current and voltage. Increasing the bias current from 0.56 to 0.84 was shown to alter the preferred orientation from (111) to (220), increase the deposition rate, and lead to a corresponding increase in film thickness. The surface morphology of all titanium nitride samples exhibited tapered planes attributable to the low bias current and voltage (−30 V). The maximum hardness values were as follows: DC mode (23 GPa) and pulsed-DC mode (19 GPa). The lower hardness values of pulsed-DC samples can be attributed to residual stress, preferred orientation, and surface morphology. The surface of the samples was shown to be hydrophobic, with contact angles of >100°.

Kinetic study about the effect of electric field and contact time of high voltage impulse on reduction of Ca<sup>2+</sup> concentration

Kinetic study about the effect of electric field and contact time of high voltage impulse on reduction of Ca<sup>2+</sup> concentration

Wybrane właściwości wysokoczęstotliwościowych inicjatorów i stabilizatorów łuku elektrycznego urządzeń spawalniczych. Cz. 1. Urządzenia z łukiem swobodnym

The article presents selected physical properties of electric arc used in welding engineering as well as discusses differences in requirements concerning ionisers used to initiate and re-initiate electric arc. In addition, the article compares properties of ioniser systems used to stabilise electric arc burning as well as discusses spark gap and semiconductor systems generating high-frequency and high-voltage impulses used to generate spark discharges. The article also discusses the effect of ioniser operation after the modification of static current-voltage characteristics, enabling the modelling of dynamic states of electric arc.

Kinetic Study of CaCO3 Precipitation Accelerated by High Voltage Impulse

Objectives : Determination of reaction order (n) and rate constants (k) of the CaCO<sub>3</sub> scale formation reaction that was accelerated by the HVI (high voltage impulse) induction.Methods : HVI was inducted to the synthetic solution containing 2.5 mM of Ca<sup>2+</sup> ion at different temperatures of 25, 40, 60℃. The concentration of Ca<sup>2+</sup> ion has been monitored as voltages of the HVI increased from 0 to 5, 10, 15 kV. Reaction order and the rate constants of the CaCO<sub>3</sub> formation reaction were determined with the experimental dataset of Ca<sup>2+</sup> concentration vs. time plots.Results and Discussion : The CaCO<sub>3</sub> formation was determined to follow two-molecules 2<sup>nd</sup> order reaction. The reaction rate constant, k increased as temperature and the applied voltages of HVI increased. The rate constant, k at 25℃ and 15 kV of HVI was 8.2×10<sup>-3</sup> L/(mmol･hr), which was 2.7 times greater than the k of the control at 25℃, 3.0×10<sup>-3</sup> L/(mmol･hr).Conclusions : The reaction of CaCO<sub>3</sub> formation was accelerated by HVI as the applied voltages of HVI increased, indicating that the HVI could be used as an alternative desalting technology for scale control.

Design and concept proof of an inductive impulse self-destructor in sense-and-react countermeasure against physical attacks

This paper presents an inductive impulse self-destruction circuit utilized in a sense-and-react IC-level countermeasure against physical attacks on a cryptographic processor. Triggered upon an alarm signal assertion by an integrated attack sensor, the proposed circuit instantaneously generates >10 V high-voltage impulse to permanently destruct the cryptographic processor for enhancing tamper resiliency. A compact design with only a single on-chip inductor and a transistor significantly saves the hardware overhead. The inductor accumulates large electric energy in its magnetic field and the switch transistor suddenly opens the accumulated energy to boost the impulse voltage in an inertial manner. Since the inductor is drawn over the cryptographic core by existing on-chip IC interconnections, no extra area for the inductor and no any optional IC process steps are needed. This fully standard CMOS compatible, complete circuit solution, results in no fabrication cost penalty. A prototype implemented in both discrete components and a 0.18 μm standard CMOS process successfully demonstrated the-proof-of-concept.

Design of 4-stage Marx generator using gas discharge tube

In this paper, a Marx generator voltage multiplier as an impulse generator made of multi-stage resistors and capacitors to generate a high voltage is proposed. In order to generate a high voltage pulse, a number of capacitors are connected in parallel to charge up during on time and then in series to generate higher voltage during off period. In this research, a 6kV Marx generator voltage multiplier is designed using gas discharge tube (GDT) as an electronic switch to breakdown voltage. The Marx generator circuit is designed to charge the storage capacitor for high impulse voltage and current generator applications. According to IEC 61000-4-5 class 4 standards, the storage capacitor must be charged up to 4 kV. The results show that the proposed Marx generator can produce voltages up to 6.8 kV. However, the storage capacitor could be charged up to 1 kV, instead of 4 kV in the standard. That is because the output impulse voltage has narrow time period.

Impulsive Breakdown Characteristics of Solid–Gas Interfaces

Comprehensive knowledge and understanding of the breakdown behavior of solid–gas interfaces are important for the development, optimization, and coordination of insulation in practical high-voltage (HV) gas-insulated systems (GISs) that are widely used in the power and pulsed power industries. However, despite significant research efforts focused on the characterization of the breakdown parameters and properties of complex gas-filled HV systems, the basic mechanisms that underpin the development of discharges in such solid–gas topologies are not fully understood. This lack of knowledge is particularly noticeable in the case of solid–gas interfaces stressed with HV impulses. This study is aimed at the experimental investigation of the breakdown behavior of solid–gas interfaces, formed between solid dielectrics and common gases: dry air, N2, and CO2 at atmospheric pressure. Four different solid-dielectric materials, PTFE, HDPE, Delrin, and Macor, with relative permittivities in the range from 2.1 to 6.3, were used in this work. The solid–gas interfaces formed by these dielectric materials and the surrounding gases were stressed with positive and negative HV impulses. The breakdown voltage and time to breakdown were obtained for all combinations of solid–gas interfaces using both positive and negative impulses, with a nominal rise time of $\sim 1.9~\mu \text{s}$ . A digital camera operated in the open-shutter regime was used to obtain images of the breakdown spark channels that were classified according to their propagation paths. The results obtained in this study will help in further understanding of the breakdown behavior of solid–gas interfaces and can be used in the development and optimization of dielectric topologies for use in GISs.

Reference Switching Impulse Voltage Measuring System Based on Correcting the Voltage Divider Response With Software

The performance of a high-voltage switching impulse (SI) measurement system is highly dependent on the characteristics of the used voltage divider. Self-built or commercial voltage dividers do not always fulfill the requirements set for reference-level devices. Software corrections to improve the non-ideal divider response are easy to implement. This article describes the traceability and performance of the SI measurement systems of VTT MIKES up to 400 kV. Traceability is based on a calculable impulse voltage calibrator, which is used for calibration of a reference digitizer and a 10-kV divider. The 10-kV divider is then used to calibrate the 400-kV modular divider. Responses of both dividers are corrected using two different software methods. Implementation of these software methods allows state-of-the-art impulse parameter uncertainties. The most significant uncertainty component of time to peak is related to its definition and evaluation according to IEC 60060-1:2010 and IEC 61083–2:2013.

Schlieren Images of Negative Streamer and Leader Formations in CO2 and a CF3I-CO2 Electronegative Gas Mixture

In electrical networks, SF6 gas is currently used to insulate high-voltage equipment, however, due to its high environmental impact, new alternatives such as CO2 and electronegative gas mixtures such as CF3I-CO2 are being trialled to replace SF6 and create a sustainable energy system. A high-voltage lightning impulse (1.2 μs/50 μs) was used to approximate the disturbance in a high-voltage electrical network caused by a lightning strike and helped to identify the likely streamer and leader formations in different gases insulating a piece of gas insulated switchgear. In this paper, the theoretical and practical aspects of electrical streamer and leader formations in pure CO2 and an electronegative gas mixture of CF3I-CO2 are examined using schlieren videography in small length rod-plane gas gaps between 20 and 50 mm in length. Schlieren allows the examination of gas density in streamer formations and for the differences in weakly attaching gases, such as CO2, and electronegative gas mixtures, such as CF3I-CO2, to be studied. The gas pressure is varied in order to examine the differences in streamer and leader formation as the gas density is varied and hence the probability of electron collision is varied.

Substantiation of criteria and methods for estimating efficiency of the electric impulse process of plant material

One of the most effective ways to prepare for extracting or removing intracellular fluid from plant material is its electric impulse treatment at initial processing stage before squeezing juice, dehydrating raw materials, drying materials, etc. As the parameters and modes that determine this process can be identified only experimentally, a device including a high-voltage impulse generator was designed. Plant tissue damage degree was assessed by changing resistance and phase shift. Intensive juice extraction was observed when high-voltage impulses in the amount of up to 100 units were supplied to plant material. With continued processing and increase in the number of impact impulses, the intensity of juice yield decreased, and the expended energy was spent on heating the plant material. The evaluation method based on quantitative analysis of pulse shape of flowing measuring current is proposed. The designed digital control device allows confirming the dependence of measured electrophysical parameters on changes occurring in plant material caused by electric impulse processing. The designed algorithm can be used as the basis of automatic control system operation for electroimpulse processing of plant materials before pressing.

Applications of High-voltage Resistor Based on Saline Solution in High-voltage Impulse Generation and Measureme

Applications of High-voltage Resistor Based on Saline Solution in High-voltage Impulse Generation and Measureme

Fast actuation properties of several typical IL-based ionic electro-active polymers under high impulse voltage

Slow deformation is an issue that restrains engineering applications of ionic electroactive polymers (EAP). The application of a high impulse voltage has been proposed to accelerate the deformation of water based ionic polymer-metal composites (IPMC). In this paper, focused on ionic liquid (IL) based ionic EAPs, ionic polymer carbon composites (IPCC), IL–IPMC, ionic and capacitive laminates, and bucky gel actuators were selected to verify the effectiveness of the high impulse voltage method. All four were able to be accelerated more than tenfold under high impulse voltages. To investigate the limitations of the high impulse voltage method, constant pulse width measurements were performed on IPCC and IL–IPMC. The deformation speed was almost linear with the pulse amplitude before it reached the maximum deformation. On setting a constant pulse width, a large deformation and a higher speed could be obtained by increasing the pulse amplitude. Additionally, by fixing the pulse amplitude, extending the pulse width induced a larger deformation at a certain speed. Finally, the consumption power and heat issues were investigated via cycling tests. A shorter cycle time (higher frequency) and a higher pulse amplitude led to larger power consumption and higher temperature. The ionic EAPs damaged at high temperature (usually over 100 °C), which is probably due to the positive feedback between Joule heating and ion mobility. In addition to the pulse width, the pulse frequency and amplitude require carefully control when using a high impulse voltage.

An experimental work on effect of bending down conductor with reinforced concrete

Down conductor is one of the pivotal parts of the Lightning Protection System (LPS) that diverting the lightning current captured by the air termination system to the earth termination system in each protected structure. A straight down conductor, is ideally suited for the best-case scenario regarding reliability and safety protection. One to aesthetical aspects, down conductor is undesirably bent in most current buildings. However, only the primary bare type of a down conductor is undergone such process, and bent at a certain degree which depending on the structure itself. Hence, this study is to investigate the bending degree effect on down conductors, by looking at breakdown voltage around the bent area with the presence of concrete wall and reinforcement bar. This experimental work conducted on a reduced scale of reinforced concrete which tested with high impulse voltage. It was determined that the bending down conductors has a significant effect on the bent (vertex) area with the interaction of concrete wall and reinforcement bar.